Temp Gauge Reads Low

[Sri Ram]

My factory dash gauge used to read right in the middle of normal (straight up and down) when the engine got up to temp. Now it comes up about as quick as usual, but stops at the low end of normal (toward the left). I grounded the lead and the gauge pegged at the high end (on the right). Is there a spec for checking the sensor itself before I spend $150 on a new one? The sensor is at the back of the head on the left side of the engine.

 

[boatpuller]

Maybe the temperature is just lower since it's the middle of June and it's 25 degrees cooler than it's supposed to be out!







Sorry to hijack your thread, that seems pretty steep $$$$ for a temp sensor, is that a dealer price???

 

[Sri Ram]

is that a dealer price???

no, it's a Cummins price. The dealer price is $180!

 

[Paychk]

no, it's a Cummins price. The dealer price is $180!

Look up your local Case Equipment dealer in the yellow pages and take your "Engine Serial Number" ESN with you and order it through them. A lot cheaper.

 

[Greenleaf]

I vote for a westach or, maybe an ISSPRO temp gauge. It won't be indicated as engine temp though. You'll have to remember why you installed that gauge.



Another option, common to shade tree gurues of which I am not, is the really really really super cheap, yet dependable Stewart Warner mechanical from NAPA.



Any are better than the factory "guess what temp I'm showing now" method of madness.

 

[JLEONARD]

I guess I would first want to know whether the gage is reading wrong, or the engine is not running at the correct temperature.

You'll need a non contact temp gun to check this.

 

[Sri Ram]

Thanks for the replies. I checked Alldata and found only the same information contained in my Dodge factory service manual. I looked in a Mitchell service manual from 1991 and found this:



To check the gauge, disconnect the sending unit lead and ground it. A properly functioning gauge will read at or above the high end of its range.



Using an ohmeter, check resistance between the sending unit terminal and the engine block. If the ohmeter reads zero or infinite resistance, replace the sending unit. If it reads between zero and infinity, the sending unit MAY be faulty. Compare with a known good sending unit.



I haven't had time to try the above, but will later today.

I vote for a westach or, maybe an ISSPRO temp gauge. It won't be indicated as engine temp though. You'll have to remember why you installed that gauge

It would be indicated as water temperature or some such. I agree with your advice to install a reliable gauge with actual numbers. Where do you recommend installing the sending unit?

 

[GHarman]

Just a thought

Went through some electrical issues with "Old Ugly" this last winter. Among them was the speedometer sending unit and wiring harness. My instrument cluster was at fault on the speedometer issue. I picked up a used unit from a salvage yard that cured the Speedometer issue and "lo and behold", all my gauges read completely different from the old instrument cluster. While not "in calibrated ranges" they were far higher on the scales than the old cluster. The used cluster cost ~ $70. 00 if I remember correctly. Nothing like the exact reading but better than no reading. GregH

 

[Greenleaf]

The OEM sending unit can be removed. If you don't like working back that far, you can remove just about any of the cyl head pipe plugs. There are two I believe, along the side, right near the fuel filter, tucked under the intake casting and then another at the front (top side)of the engine right next to the thermostat.



I installed a westach universal for a friend and they are very simple. The Isspro, which I have, requires that green box to mount. I think they call that the "driver". Seems very complicated but works very well.

 

[Sri Ram]

Look up your local Case Equipment dealer in the yellow pages and take your "Engine Serial Number" ESN with you and order it through them. A lot cheaper.

I called my local Case dealer. Parts guy said it had to be a Case serial number.



I checked continuity this morning with engine cold 1. 301 ohms, and again after commuting on the highway for a half-hour engine hot 280. 500 ohms. Since the sending unit has a resistance between zero and infinity, I guess I'll compare to a new one. Before I do that, I'm going to check the thermostat just to make sure it's not sticking or installed wrong.

 

[JLEONARD]

Just check it with a temp gun. In a few seconds you'll know.

You can buy them cheap now for about $20. Awsum tool to have for many purposes.

 

[dpuckett]

I know this isnt exactly the time of year to be trying this, but how is your heater? Does it blow 140deg air, or whatever the FSM calls for? If so, I'd say there is nothing wrong mechanically. I agree with the Greenleaf method- install a SW mechanical gauge in there. Removal of the ashtray allows the use of 2 gauges in a discreet location.



Daniel